**There is a belief in some quarters that the DZ302 produced well in excess of the 296 Bhp quoted by Chevrolet. I can understand why folk would think that but that is absolutely not the case. I have seen figures quoted of a minimum of 350 Bhp and as high as 370. With figures like that a Can Am would run a ¼ mile in the 12’s and with the right gearing and rubber break into the 11’s…something not possible with an otherwise stock Can Am 302… 296Bhp as quoted by Chevrolet is an amazingly accurate nett figure for this engine.
SO…there is no question about the theory, you need around 400 bhp to haul a machine weighing nearly 4000 lbs through the strip in 13 seconds… and here is the other side to the picture…we have established that the 389 as fitted to the test car would be producing around 350 bhp net…not nearly enough power to achieve those times…something was fishy in the state of Florida.
At this point the background to the Pontiac range of V8 engines is worth explaining. Unlike the other US manufacturers who produced distinct ‘Small Block and ‘Big block’ versions of their V8 engines, Pontiac chose to run a single basic engine to cover the range. In this instance the Tempest was produced in original form with a 326 cubic inch version of the engine, the larger Catalina a 389 with the top of the range enlarged to 421 cubic inches…all from the same basic engine block design. This explains a few things, firstly the move from the original 326 to the 389 for the GTO was a bolt-in job making the switch to the larger engine a relatively simple engine swap and a minimum cost exercise. Secondly…it also made the fitment of a 421 version of the V8 into the Tempest equally easy…
Two questions need to be answered: 1. What was the true Horsepower of GTO tested and 2. What was the test weight…. These questions can only be answered by establishing the level of intent in preparing the cars for this road test, so we will deal with the second question first.
As part of the Works orders arranged by Wangers to build the cars, he included a request for the removal of all sound insulation material. This shows that the exercise was a well-planned activity. Exactly how much weight was removed in the process would be a guess, however, I can give an estimate. Again, in a similar programme being responsible for building the reinforced bodyshells for Geoff Mortimer’s Chevairs in the 70’s, the removal of all insulation on those cars including underbody bitumen spray worked out at 50Lbs. I will guess the GTO to be around 70Lbs.
The other very significant matter was that with Pontiac cleaning up in competition in the early sixties, their Super Duty (SD) range of 389 and 421 V8’s were the products of those extremely experienced engine men. The issue of the 421 cubic inch engine in the road test was cleared up in the late 90’s with Wangers acknowledging, as suspected by most, that the car(s) did in fact have the bigger engine fitted for the test. Given these circumstances, it is highly unlikely that if Wangers was going to go to the trouble of removing weight from the cars that he would not utilise the substantial engine expertise available at both Pontiac engineering and Royal Pontiac to include blueprinting the 421. Which probably included the fitting of the available big valve ‘heads. I do not believe engine work went beyond that, simply because turning the engine into a higher rpm revver would have been a dead giveaway…Max Rpm for the test was quoted at a very mild 5600.
So…given the background, this is the specification at which I believe the cars were tested:
- Blueprinted 421 producing approximately 390 Bhp nett installed.
- As tested weight approximately 3770 lbs
That spec would result in the times obtained by C&D. We need to remember that a tri-carb GTO running the 389/348Bhp package quoted ex-factory, even with the good gearing spec, would at best run a ¼ over a second slower in a 14.5…!
The critics back in March were dead right… the test cars were ‘Ringers’
So, what do we learn from all this?. Firstly as engineers we like to make sure everything is ‘black and white’ by checking that all we do makes engineering sense. In a perfect world the best engineered product and sticking to the rules would win every time…but we do not live in a perfect world. We live in a world where perception is often more powerful than fact and at some stage in the game and under the right circumstances engineers need to let go and allow magic to be performed by those who manage those perceptions. In the end It is a game of calculated risk and a very fine line. In this particular case that risk was managed by someone who knew the territory…and he took an educated guess at how far he could bend the rules… Wangers, De Lorean and the team then held their collective breath and won the day.
I suppose the real measurement of whether the ‘right thing’ was done is the assessment of how the car and the associated image it created managed after that…the answer of course is self-evident…the ‘Goat’ today is the benchmark by which we remember the Muscle car era. The result was deservedly spectacular… proving to us that sometimes a little of the “Smoke and Mirrors” helps to get the job done… You be The Judge.